Manhole cover and frame.



No. 810,969. 7 PATENTED JAN. 30, 1906. M. H. ODONNELL.

MANHOLE COVER AND FRAME.

1 APPLIOATIQ-N FILED APR. 19, 1905.

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MICHAEL H. ODONNELL, OF DETROIT, MICHIGAN.

MANHOLE COVER AND FRAME.

Specification of Letters Patent.

Patented Jan. 30, 1906.

Application filed April 19, 1905. Serial No. 256,402.

To all whom it may concern:

Be it known that I, MrcHAEL H. ODON- NELL, a citizen of the United States, residing at Detroit, county of Wayne, State of Michigan, have invented a certain new and useful Improvement in Manhole Covers and Frames; and I declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification.

My invention relates to an improvement in manhole covers and frames shown in the accompanying drawings, and more particularly set forth in the following specification and claims.

In the drawings, Figure 1 is a perspective View of a circular manhole, showing the cover closed. Fig. 2 is a cross sectional view through the frame to which the cover is hinged looking toward the cover, which in this case is rectangular. Fig. 3 is a crosssectional view at right angles to Fig. 2, showing the cover raised and the guard-frame protecting the opening in position.

This invention has for its object an improvement in manhole-covers, whereby in the event of an explosion due to the accumulation of gas the cover being forced open will immediately return to its seat after the pressure of gas is relieved, the construction eing such that no undue strain is brought to bear'upon the hinges and the automatic closing of the cover assured.

A further object is a safety-guard to protect the opening when it is desired to have the cover raised while working in the conduit leading to the manhole.

A further object is the means employed for supporting the portable ladder and the construction of the ladder itself.

Referring to the letters of reference shown in the drawings, A is the supporting-frame for the cover, which may be circular, as shown in Fig. 1, or rectangular, as shown in Figs. 2 and 3. This is laid in the usual manner, the top being on a plane with the street or sidewalk.

B is the cover, provided with the hingelugs B formed thereon. and pivoted in the cross-bar A, which is preferably integral with the walls of the frame A.

C C are hinge-pins entering a suitable aperture in the cross-bar A and through openings in the lugs B. The ends of the pins are bent at right angles, which when turned so as to lodge within the recesses a a, formed in the cross-bar A, serve to lock the pins against displacement.

It will be observed by reference to Fig. 3 that the cover when raised is forced to an angle that will readily return it to its seat in the event of the cover being displaced .by an explosion. This is attained by slanting the back of the cross-bar A, as shown at a, which in conjunction with the projecting portion a of the frame serves to hold the cover at an angle. A further object of this formation of the frame is to relieve the hinges of any undue strain caused by a violent opening of the cover, as the cover in being forced open will come in contact with the projecting portion a of the frame and against the wall A, thereby relieving the hinge-pins of the strain that would otherwise be exerted upon them.

D is a suitable guard-frame pivoted to lugs formed on the under side of the cover, as shown at d, and jointed at d to upright standards provided at their lower ends with offset portions d designed to enter sockets formed in the frame A. These sockets are preferably open through the wall of the frame so as to insure the discharge of any dirt that might otherwise accumulate in them. In closing the cover the guard-frame D being released it hangs suspended from the cover in the manhole. This form of guard-frame may be dispensed with and the usual portable one employed, if desired.

Having thus described my invention, what I claim is- 1. In a manhole-cover, the supportingframe, a cross member having an inclined face, the cover hinged to said cross member, the construction being such that when the cover is forced open it will bear against the supporting-wall and cross member, substantially as described.

2. In a manhole cover and frame, the supporting-frame, provided with a cross member to which the cover is hinged, the construction of said frame and cross member being such that when the cover is forced upward it will stand at an angle when raised, wherebyit will automatically return to its seat, substantially as described.

3. In a manhole cover and frame, the supporting-frame having a cross member to which the cover is hinged, the cover formed with hinge-lugs designed to enter suitable recesses in the cross member, hinge -pins adapted to enter apertures provided in the lugs of the cover and the cross member, said pins provided with means for locking them against displacement, substantially as described.

4. In a manhole cover and frame, the supporting-frame provided with a cross member to which the cover is hinged, the construction of said frame and cross member being such that when thecover is forced upward it will be restrained at an angle from which it will automatically return to its seat if otherwise unsupported, in combination with the guard-frame arranged to hold the cover up and guard the opening, substantially as described.

5. In a manhole cover and frame, the supporting-frame provided with a cross member to which the cover is hinged, the construction of said frame and cross member being such that when the cover is forced upward it wise unsupported, in combination with a guard-frame consisting of a rectangular upper section hinged to the cover, and two depending lugs supporting the rectangular frame from the corners when the cover is raised, substantially as described.

6. In a manhole cover and frame the combination of the frame, the cover hinged to the frame and means consisting of a stop above the hinge on one side and a Stop below the hinge on the other side to take the strain of the cover from the hinge, when the cover is forced open by the explosion of gas or other causes, substantially as described.

In testimony whereof I ign thi specification in the presence of two witnesses.

MICHAEL H. ODONNELL.

Witnesses:

S. E. THOMAS, AN E .P- ODQNNELL, 

